Vapor electric device.



E. WEINTRAUB.

VAPOR ELECTRIC DEVICE.

APPLICATION FILED mms3, 1913.

Patented May 4, 1915.

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g llwewp or Ezechiel Welrtfaub Curre nt Wt, esses H1 oy lilFFICE.

EZECHIEL WEINTBAUB, OF LYNN, MASSACHUSETTS, ASSIGNOR TO GENERAL EJ'.EC'J.RICv

' COMPANY, A CORPORATION OF NEW YORK.

'VAPOR ELECTRIC DEVICE.

inaaice.

Specification of Letters Patent.

Patented May 4, 1915.

Continuation in part of application Serial No. 698,741, led May 21, 1912. This application filed March 13,n

' 1913. Serial No. 753,946.

T0 all 'wlwm it may concern Be it known that I, EzEcHInL WEINTRAUB, a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Vapor Electric Devices, of which the following is a specification.

The present application is in part a continuation of my former application, Serial No. 698,741., filed May 21', 1912.

My invention relates to vapor electric devices, particularly to what is known as the high pressurelarc lamp which consists essentially of a light-transmitting refractory envelop, such as a fused quartz tube in which a mercury, or other vapor are, is operated at a relatively high temperature.

One of the best distinctions that may be drawn between the well-known low pressure mercury are lamp and the high pressure lamp is the following: A low pressure lamp takes about the same voltage and energy at starting as it does at normal operation, while a high pressure lamp starts at a much lower voltage and at starting takes less energy than inder normal operating conditions when t e lamp has come to a final equilibrium. On multiple circuits the starting current is high and is reduced as the lamp assumes equilibrium. The high pressure lamp as now commonly constructed and proportioned operates with an energy consumption of more than 25 watts per inch in a tube about one-half inch in diameter. In fact, theenergy consumption commonl is about 80 to 100 watts per inch in a tu e of this size. The conditions in a lamp of this character differ materially from those of the long, low pressure glass-inclosed mercury arc lamp. A number of conductive materials may be used for the Vanode in the low pressure lamp. Mercury, iron, latinum, and graphite may be interchanged) for one anotherwithout a marked change in the arc. In a high pressure lamp conditions are quite different. All the single walled high pressure mercury arc lamps that have appeared on the market have been provided with ground plug seals for the introduction of current andl this construction practically precludes the use of a solid anode on account of the high temperature developed atv the anode which would endanger the seal. The use ofmercury as anode material not only limits the lainp'to a narrow range of service, as will be more fully explained,- but what is equally important, a mercury anode needlessly increases the vapor pressure in the lamp by its rapid volatilization. The increased vapor pressure results in an increased electrical resistance, and :with a given impressed voltage correspondingly decreased energy input. As the efficiency of the lamp decreases at a greater rate than the energy consumption, the economy of a high pressure`lamp on commercial 110 volt circuits has been low and this fact has practically limited the high pressure Amercury lamp to large units operated at higher voltages. In the so-called lGerman type of quartz lamp cooling fins are used at the electrodes for the purpose of reducing this vapor ressure, and in the French type a large ano e condensing chamber is used for the same purpose but these devices themselves waste energy and lower the efficiency. At 110 volts the ofliciencv of either lamp is only about 1.8 to 1.6 watts per candle power when losses in a series resistance, etc., are included.

By the use of the so-called graded seal comprising a tungsten wire sealedA into a sodium-magnesium boro-silicate glass which blends or merges with the quartz wall to form a continuous structure, a high pressure5 mercury lamp may be built havlng a solid anode. In experimenting with different solid conductive materials -for the anode, I' have discovered that most of them rapidly disintegrate and blacken the tube so that their successful commercial use is practically excluded on account of the ineilicieney of the lamp due to the eiliect mentionedk This rapid disintegration is observed 'evenV in the leading-in conductor 'joined to the anode. In my opinion it is not soefly due to the temperature of the anode asa material like graphite, which is highly refractory and does not easily vaporize, disintegrates very rapidly under the peculiar conditions existing in a lamp of this kind although its temperatureis not much higher than 1100 to 1200 degrees. A graphite filament will operate almost indefinitely in an incandescent lamp at this temperature. Another4 dificulty encountered with y anode materials even as refractory as platinum is the melt-y ing of the anode by the high starting current of the lamp.

My inventionas will be pointed out l -*vh greater particularity in the claims comprises a high pressure vapor lamp having a solid anode, in particular, a tungsten anode, situated remote from both condensing space, or other cooling means and liquefied mer- .cury in the tube. Other novel features will be pointed out With particularity in the claims.

In the attached drawings, Figure 1 is a `perspective view of a single-walled vapor lamp illustrating my invention; Fig. 2 illustrates a modification; Fig. 3 isa detail view showing the cathodeun'der operating conditions.; 4 shows a A lamp` adapted for use in alternating current circuits;4 Fig. 5 shows volt-ampere curves contrasting my improved lamp with the I-prior form; and Fig. A6 shows the relation between `energy input and elficiency'in my improved lamp.

When a solid anode preferably of pure tungsten, in a ductile state is used in the lamp, the resistance of the arc is lowered enabling it to be utilized with high eliiciency on low voltage circuits. The blackening of` the tube is entirely avoided or is reduced to such a small amount as to be of little harm. When carefully prepared pure ductile tungsten is usedr and the sealing-in process carried out so' as to avoid all oxidation; the blackening of the tube is in fact entirely absent. Other refractory materials such as -molybdenum and tantalum may also be used. I have found also that under these conditions, the relation between energy input and eiiiciency when plotted respectively as abscissa and ordinate are represented by a constantl rising curve without minimum point. A llamp thus constructed having a length of say 32 and a diameter of about may be operated on a .110 volt circuit in series with aresistance of about 6-8 ohms, with an. efficiency of 0.45 to 0.5 watts per mean spherical candle power across the arc or even higher. The efficiency of the unit with all accessories is about 0.7 watts per mean spherical candle power. This includes all losses, such as loss in the series resistance, absorption`- fof light in a clear globe, and the like. The voltage drop in a lamp operating at threliiciency` is about 22 volts per inchbf length. The voltage drop depends to alarge .extent upon the shape of the tube nearthe cathode and the size of thel cathode mercury surface. 'The change from mercury to a solid anode material, together with the structural changes made possible thereby, so modifies the volt-ampere curve of the high pressure lam that a new field is opened up for it, name y, its o eration on series, or constant current, varia le voltage, lighting circuits. Up to the present the high pressure vapor lamp has not been available for economical operation on series circuits for reasons more fully explained hereinafter, and this fact has greatly llimited the use of the lamp in this country. On series circuits, the efficiency of Amy improved lamp is even higher than on multiple circuits because of the absence 'of a steadying resistance. In a unit of GOO-700 watts the very excellent eliciency of 0.35 Watts per mean spherical candle power is obtained. Another-very important advantage resultingfrom the use of a solid refractory anode is to be found in the simplicity and high etliciency of the high pressure alternating current mercury lamp. It has beeny attempted heretofore to use mercury anodes in this and a coperating tungsten anode 3. The 1 tungsten anode is preferably in the form of a coiled wire, the outer turn of the spiral being continued as the leading-in wire iso that a unitary structure results.l As the point of greatest heat is at the center this method is conducive to keeping the seal cooler than when the wire joins the center of the anode. The anode leading-in wire 4 and also cathode lead Wire 5 consist of tungsten and are both sealed by fusion into a sodium-magnesium boro-silicate glass, or equivalent low expansion glass, which is integrally joinedto the silica wall by gradually merging therewith in composition. In other words, the basic constituents of the glass material decreases until the material blen ys with the `pure quartz. ab've the anode is contracted as much as possible so that practically no idle condensing space exists near the same. 4The fiat shape of the anode favors the attainment of this result. The lamp is started by tilting' so that the cathode material comes in contact with theanode and thereby strikes the arc.. Tiltin mechanism of this kind is well known in t e art, so will not be described herein.

In the modified form of lamp shown in Fig. 2, the idle condensingspace back of the anode 6 is filled up by refractory material such as quartz block 7 embedded in granules of quartz silica 8 in order to completely fill out .the space. This construction The space.

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masses ment of the arc in a direction perpendieu-y lar to the cathode. If the mercury were permitted to remain at ythe level at which the body of mercury line assumes in Fig. 1tlie quartz near the bend of the arc would be heated to redness and in some cases soften and blacken. By providing a space back of the cathode the ressure developed within the tube lowers tie mercury level by push-v ing the mercury upward into the chamber' 9 as shown in Fig. 3. yThe arc is thus removed from proximity with the silica envelop.

The advantage of a solid anode in a series lamp' has already been referred to but its effect may be m'ore fully understood by ref erence to Fig. 5 in which the volt ampere relations in the lamp having a mercury anode and a lamp having a solid anode are plotted as ordinate and abscissa as indicated.

As will be noted, by reference to curve A,

the volt ampere curve for a lamp with a mercury anode rises very sharply at the current value between two and three amperes. At this value ofV current the lamp is unstable as its voltage constantly increases. In a constant current variable voltage circuit the voltage soon becomes great enough to destroy the lamp. If it were desired to operate such a lamp on a constant current circuit it would have to be'run at a very uneconomical low current value. When a solid .anode is used the volt-ampere curve whlle maintaining its general shape does not begin to rise sharply until the current value has become considerably larger, as shown very clearly by curve B. This change in the volt- 4ampere characteristic makes it possible to run the arc at a higher current value without instability and difference in operating current improves the eiiciency by 50-100%. As a series resistance whchvconsumes about 25% of the total energy of a unit is not required in a series circuit a correspondingly higher eliiciency may be- 'ichieved with the quartz lamp in this new eld.

The structure of the alternating form of lamp shown in Fig. 4 is ,very simple; the anodes 10 and 11 are placed quite close together in the branched ends 12 and 13 of the envelop. The two half Wave arcs running to the cathode, 14 from the two anodes may be superimposed in the same tube thereby getting higher eiiiciency. The construe tion is sov chosen that no mercury can con dense and drop on the anodes as this might cause arcing as already described.

As already stated and as shown in Fig. 6, the curve obtained when plotting energy input against Aefficiency rises sharply. An increase in energy consumption thus results in considerably more than a. proportionate increase in eiiiciency.

In order that the high pressure vapor arc may be clearly distinguished from the low already indicated above are enumerated for the purpose of explaining the language of the appended claims: 1. The high pressure arc requires a starting current substantially higher than the operating current. 2. After the envelop becomes heated and the arc is operating' normally the high pressure arc contracts to a comparatively narrow zone instead of filling the entire space within the envelop as does the low pressure lamp. 3. As indicated in Fig. 5, the high pressure arc operates when the voltage exceeds a certain value with asubstantially constant current.

In myco ending application Serial No. 753,947, file concurrently with the present application, I have described and claimed a method of operating the type of lamp embodying the present invention. According to this method the cooling capacity of the cathode or of the lamp in the immediate vicinity of the cathode is so adjusted that the arc may be run at higher current input before approaching the critical value of current at which the voltage increases so abruptly with increases of current as to make the operation of the arc unstable on series circuits.

What I claim as new and desire to secure by Letters Patent of the United States, is,-

1. A vapor electric device com rising'a quartz envelop, a mercury catho e at one end of said envelop, an anode consisting of a metal more refractory than platinum at the opposite end lof said envelop, and current-conveying conductors for said 4electrodes the part of the anode conductor adjacent the anode proper also consisting of a metal more refractory vthan platinum, and theenvelop section surrounding the anode and the anode conductor being proportioned to assume a temperature at which substantially no mercury will condense when said device is operating with an energy input sufficient to produce a high pressure arc.

2. A vapor electric' lamp comprising a mercury cathode, a tungsten anode, current-conveying conductors for said electrodes sealed into said envelop, the part of the anode conductor adjacent the anode also consisting of tungsten, andan inclosing quartz envelop which is contracted upon the anode conductor to proportion the space envelop and current sup ly wires for said electrodes, the 'art of t e anode wire adjoining the ano e consisting of a metal more refractor than platinum, and the parts of said enve op surrounding the anode being arranged and proportioned to assume a, temperature at which no globules of mercury Will form large enough to vdrop through the arc path when said lamp is operated` with an energy input sulicient to produce a high pressure arc.

4.` A lamp comprisin a tubular envelop consisting largely of silica, a. cathode of mercury at one end of said envelop, an anode of mctalmore refracto than latinum kat the opposite end of sald enve op, current conveying conductors for said electrodes, the anode conductor consisting of metal more refractory than platinum, and a seal of zones EZECHIEL WEINTRAUB.

Witnesses:

JOHN A. MCMANUS, Jr. FRANK G. HATrIE. 

